Sound is perhaps the most important of all the senses because airplanes really do talk. Sadly, we're not always listening. When we're flying with noise canceling headsets, concentrating on learning a new training maneuver--or perhaps flying an instrument approach in actual weather conditions--we may fail to hear all that our airplane is telling us.
Simply put, increasing noise means the aircraft is accelerating; decreasing noise means the aircraft is slowing. In both cases, this normally applies to the aircraft's pitch attitude with nose-low being accelerating and nose-high decelerating. Of course, the sound also changes with the aircraft's configuration. More drag means more noise, so if you're on final and you don't hear a change, you might want to re-check your flap position and, if appropriate, your landing gear.
A Cessna 152 instructor once approached me to get checked out in an open-cockpit Great Lakes biplane. I knew he would be a challenge when he asked me about V speeds. After reminding him that this was a replica 1930s-vintage biplane with "N" struts on the wings, I told him that when the "N" was tilted back, we were climbing, when it was level, we were in cruise flight, and when it tilted forward, we were descending. More important, the wind streaming over the flying and landing wires would tell us our airspeed, and we never, ever use V speeds in an aircraft like this. As I recall, he never got checked out, and although most pilots will never care to pilot this type of airplane, the principles of tuning into sound are the same--all we have to do is listen.
I recommend that every training flight include sound instruction. All kidding aside, teaching sound awareness is as simple as having the student fly the airplane with his eyes closed. (Instructors may wish to guard the controls to ensure smooth flight and protect against severe unusual attitudes.) Flying blind accomplishes several things. First, the student can tune into the sounds associated with various pitch attitudes; second, it teaches him or her to trust the instruments, not the inner ear.
Smell is often overlooked, but tuning in can identify problems with your airplane. The most important odor to identify is fuel. Some aircraft use feeder tanks that are located directly in front of the instrument panel, while others have shutoff valves an arm's length away. Either one places fuel lines in close proximity to the pilot. Should you smell a fuel leak, land at the nearest suitable airport and sort it out. This is another good reason not to smoke in aircraft.
Burning oil has its own odor, and may indicate an impending valve failure. It's quite likely you have already smelled scorched oil by following a car with bad rings. Engines that pour blue smoke from their exhaust are burning oil. Black smoke means they're burning an overly rich fuel mixture. As with a fuel leak, if you smell oil, take heed and land to investigate.
The most dangerous gas has no smell at all. Carbon monoxide has been responsible for numerous aircraft accidents because it gradually puts people to sleep. In light aircraft, the source is usually an exhaust leak with the poison entering through the heater vent. Carbon monoxide detectors may identify the problem, but the only solution is to vent fresh air into the cockpit.
Touch is feel and is extremely important to piloting. You can't trim an airplane if you're flying with a white-knuckle grip.
Proper flying means the aircraft is always trimmed for hands-off flight. Since the center of gravity changes with fuel burn, trimming is an ongoing process. A well-trimmed aircraft allows the pilot to feel the yoke pressures needed to maneuver the aircraft, particularly when flaring to land.
It's easy to preach proper trim and feel, but the only way to know if the aircraft is in trim is to release the controls and see what happens. I'm not referring to throwing your hands in the air; just lifting your fingers enough to see if the aircraft's pitch changes.
For students who are anxious about flying and can't seem to relax on the yoke, have them slide a pen between their index finger and the yoke. Like having a stone in their shoe, the pen's pressure will remind them to trim the aircraft.
Judgment is a whole other story, but it's gained from reading, speaking, and performing flying. Whether from good experiences or bad, judgment is gained on every flight. A thorough debrief will greatly enhance a student's training.
Understanding and applying your senses are fundamental to three-dimensional flight. Flying is more than GPS navigation. Safe piloting requires an understanding of what the flight controls are doing, and being tuned in to your aircraft will help ensure this.
Mark W. Danielson is a retired Navy pilot who currently flies for FedEx. He has been a CFI for 26 years and has flown more than 11,000 hours.